Journal of Biomedicine and Biotechnology
Volume 2005 (2005), Issue 4, Pages 301-309
doi:10.1155/JBB.2005.301
Abstract
Type I signal peptidases are important membrane-bound serine
proteases responsible for the cleavage of the signal peptide of
the proteins. These enzymes are unique serine proteases that
carry out catalysis using a serine/lysine catalytic dyad. In the
present study, we report the isolation of type I signal peptidase
from the malaria parasites Plasmodium falciparum,
Plasmodium knowlesi, and Plasmodium yoelii and
some characterization of type I signal peptidase of
Plasmodium falciparum. We show that these enzymes are
homologous to signal peptidases from various sources and also
contain the conserved boxes present in other type I signal
peptidases. The type I signal peptidase from P falciparum
is an intron-less and a single-copy gene. The results also show
that the enzyme from Plasmodium falciparum is subject to
self-cleavage and it has been demonstrated to possess type I
signal peptidase activity in E coli preprotein processing
in vivo by complementation assay. This study will be helpful in
understanding one of the important metabolic pathways “the
secretory pathway” in the parasite and should make an important
contribution in understanding the complex process of protein
targeting in the parasite.